The desirability of facilitating the harvest of various agricultural crops, especially fruit crops such as citrus fruits, is readily apparent. A number of chemical compounds capable of promoting fruit abscission has been proposed, which compounds serve to reduce the pull force necessary to remove mature fruit from the tree or plant, thereby rendering mechanical harvesting possible. Few of these compounds, however, have found practical utility, mainly owing to their tendency to injure immature fruit and cause blossom drop and/or their simultaneous defoliant effect.
One compound currently in use as a citrus fruit abscission agent is cycloheximide, i.e., 3(2- 3,5-dimethyl-2-oxocyclohexyl!-2-hydroxyethyl) glutarimide. This use is described more fully in U.S. Pat. No. 3,663,199. While the compound is indeed effective in reducing the pull force necessary to remove citrus fruit from trees, its use has been seasonally limited on some citrus varieties (e.g., Valencia oranges) since its application in an amount sufficient to cause the desired abscission, can also result in damage to immature fruit and cause leaf and bloom drop.